A deadly supervolcano lies under Yellowstone — and an eruption would emit dangerous gases and spread ash for 500 miles

Lydia Ramsey

Oct. 12, 2017, 01:54 PM

Flickr / Howard Ignatius

Yellowstone National Park may be best known for its Old Faithful geyser and its stunningwildlife, but the national park also sits atop a supervolcano that simmers just under the surface.

You can see evidence of the volcano's active state in the park's famous hydrothermal activity, includingOld Faithful, which shoots water every few hours.

Because the area's still active, researchers have been trying to determine when it might erupt again. And according to new research presented at the International Association of Volcanology and Chemistry of the Earth's Interior conference, it might take much less time for the supervolcano to go from not a problem to erupting than experts realized. Based on minerals from the last major eruption, the researchers found that the changes leading up to an eruption may happen in a matter of decades rather than thousands of years in advance as previously thought.

"It’s shocking how little time is required to take a volcanic system from being quiet and sitting there to the edge of an eruption," Hannah Shamloo, a graduate student at Arizona State University who conducted the research told The New York Times.

The impact of an eruption

The odds of the supervolcano erupting within a given year areone in 730,000, according to the US Geological Survey. But if it did blow, it could have extreme effects on surrounding areas.

For starters, the eruption could emit ash that would expand over 500 miles. For comparison, this map shows the area that the ash reached in the 1980 Mount St. Helens eruption in Washington.

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The eruption would likely cover the ground with as much as4 inches of gray ash, which could be detrimental to crops growing in the Midwest.

Molten lava at temperatures up to 1,000 degrees Fahrenheit could also ooze out, though that'd be less of a concern than the ash. And the supervolcano would spew a whole bunch of gasses as well, including sulfur dioxide, which can lead toacid rain as well as global coolingas it reflects sunlight away from the Earth.

The explosion likely wouldn't wipe out human life, but it certainly would be destructive, especially to the western half of the US.